Call function inside Joomla articles - joomla

Question

I am facing a problem. I have created a article in Joomla administrator and i have created a function in a php file. I have to call that function in that article . I don't know how do i call function in article.
Here is the code:
class modVodesbalanceHelper {
function deductBalance()
{
$db = JFactory::getDBO();
$result = null;
$user = JFactory::getUser();
if ($user->guest) {
return false;
}
$query = 'SELECT credit' .
' FROM #__vodes_credits' .
' WHERE userid = ' . (int) $user->id
;
$db->setQuery($query);
$result = $db->loadResult();
$result_final=$result-10;
$query = 'update #__vodes_credits SET credit='.$result_final.
' WHERE userid = ' . (int) $user->id
;
//echo $query;
$db->setQuery($query);
$result = $db->loadResult();
}
}
In admin panel, in article i have write this code:
<script>
window.onload=function()
{
var a=confirm("do you want to purchase this credit");
if(a)
{
document.location.href ="index.php?option=com_content&view=featured";
}
else
{
document.location.href="index.php?option=com_content&view=article&id=3";
}
}
</script>
I have to call deductBalance when user click on the "OK" of comfirm box.
Please tell me to sought it .

Answer 1

You can't add PHP to Joomla article by default. For this you need to use a 3rd party plugin. Personally, I would recommend using Sourcerer. Once installed and enabled, you can use the following in your article:
{source}
<?php
// All your PHP code
?>
{/source}
Don't include PHP files inside your article

Answer 2

I would use Sourcerer to add php code inside joomla article.
Check the sourcerer plugin to be enabled (check plugin enabled status here: extensions->plugin manager->sourcerer).
Then, use the "Insert Code" button at the bottom of your WYSIWYG editor when adding your PHP scripts. Your code should be wrapped with
{source}
//php code wrapped by <?php ?>
{/source}

Answer 3

If you need to use code directly within Joomla article then use Sourcerer as in above questions. If you feel to keep the PHP code in seperate module. Use Blank Module
Or mod_php module. Then in your Joomla Article you can place the code like this,
{loadposition}*Your Custom Module Position*{/loadposition}